L12 : Estimation of Numbers - Knowing Our Numbers , Maths, Class 6 Video Lecture

hello friends this video on
understanding numbers part 12 is brought
to you by exam furor calm know mode here
from exam now let's look at something
very interesting this little girl she
sees that the population of Delhi is 10
million somebody asked him a friend
asked her what was the population of
Delhi and she replied that the
population of Delhi is 10 million but
her friend disagrees saying that the
statistics in the newspaper said that
the population of Delhi is 9 point 8 7 1
million as on 2001 so now how the world
thinks that okay I said 10 million which
is very close to 9 point 8 7 1 million
so what do you think do you think that
the girl is right or the boy is right
now the statistics which is given by
this boy I mean which he had read in the
newspaper that gives a more accurate
value but the number which is given by
this girl is also not incorrect because
she she is just rounding off the number
she is talking about a number because it
is more easy to remember 10 million than
remembering 9 point 8 7 1 million agree
yeah so just to make sure that you
remember this approximate figure this
approximation is done and this is what
we call as estimation of numbers because
when we deal with very large numbers so
there a difference of a small doesn't
really matter let's say that if you if
you have invited 10 people to your house
and 2 of them didn't arrive so that
makes a difference because there were
only 10 people invited and now only
eight of them ever right so 2 are not
there so you actually feel
absence now let's say that instead of 10
people you have invited 1,000 people in
your house and two people didn't come up
so there is a possibility that you might
even realize that who were not present
because the total number of people the
strength is huge so in the similar way
when we talk about large numbers so
small differences don't matter much so
here we are talking in millions so air
in the population is 9 point 8 7 1
million or the population is 10 million
that approximately doesn't make much
difference so just to make it easier to
remember just to just for our
convenience to use those numbers
estimation of numbers or rounding off
numbers are often done so then exactly
do we see this rounding off numbers who
have we actually witnessed it now in the
newspaper sometimes we have seen such
news headlines which sees that
approximately 5000 people went to
witness the match now when you have
these numbers now that really doesn't
mean that exactly 5000 people where
they're in the stadium it could be four
thousand nine hundred twenty people or
it could be five thousand nineteen
people or it could even be five thousand
two hundred people so it has just been
approximated to a number which can be
easily remembered or easily interpreted
by people now when you read that
approximately four thousand nine hundred
sixty-two people went to witness the
match so it's quite difficult for you to
remember the number so how do you
remember it by rounding it off to the
nearest easily rememberable number like
five thousand similarly let's say you
have lot of coins and you count them
together to make rupees 60 now you say
that total amount that we get out of
these coins these many conch maybe these
are some ten percent twenty
coins and you made together rupees 60
now when you see the true piece 60 that
again doesn't mean that it is exactly 60
it could be 57 it could be 61 but then
again it cannot be something like 500
because 60 and 500 are like far apart
but 57 can be assumed to be 60 61 can be
assumed to be 60 but hundred or 500 or
600 11 cannot be assumed to be rupees 60
so it has to be something which is you
know very near to that number and then
you can round off to that number let's
think of another scenario let's say that
you are organizing a party and you
invited say approximately some 95 guests
now these are the number of people who
you have invited for the party but you
do not know if all of them are going to
come or if some of them are not going to
come fine if some extra people are going
to come maybe one or two extra people
might come so what do you do you make
arrangements for hundred guests because
you think that okay 95 is the number I
have invited so let me round it up to
100 so you are preparing for 100k guests
because you rounded of 95 200 just to
keep that extra buffer so in all of
these scenarios we see that we use
rounding off in our day-to-day life
often you would have seen that let's say
that you are going to the market your
mother asked you to buy something from
the nearby grocery store now whatever
she had asked you to buy that might cost
say rupees 47 all right let's say that
my costume is 60 but gently she gives
you 100 rupee note in case you need a
little more money like so in so in in
normal cases you see that you often come
across this rounding off scenario
where the amounts are generally rounded
not the amounts exactly the numbers
whenever we are talking of huge numbers
we tend to round them off to a nearest
number which is easy to remember now
generally numbers say hundred five
hundred five thousand fifty thousand the
numbers with zeros they are quite easy
to remember and also they help us to get
an estimate or they help us to make a
fairly guess about the number thank you
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